Final answer:
Mutation, gene flow, and genetic drift are three processes that drive microevolutionary change. Mutation introduces new genetic variations through changes in DNA. Gene flow brings new alleles to a population through the migration of individuals or gametes. Genetic drift refers to random fluctuations in allele frequencies due to chance events.
Step-by-step explanation:
Mutation, gene flow, and genetic drift are three main processes that drive microevolutionary change.
Mutation:
Mutation is the process of changes in an organism's DNA, which introduces new genetic variations into a gene pool. Mutations can occur spontaneously or as a result of exposure to mutagens like radiation or chemicals. This process is essential for evolution because it creates the genetic diversity that natural selection acts upon.
Gene Flow:
Gene flow occurs when individuals or gametes migrate between different populations, resulting in the exchange of alleles. This movement introduces new genetic variations into a population and can prevent genetic divergence between populations. For example, if pollen from one population of plants is carried by wind to another population, it can bring new alleles and increase the genetic diversity of the receiving population.
Genetic Drift:
Genetic drift refers to random fluctuations in allele frequencies within a population. It occurs due to chance events, such as the random segregation of alleles during reproduction or the survival of certain individuals by chance. Genetic drift is most likely to occur in small populations where chance has a greater impact on allele frequencies. Over time, genetic drift can lead to the fixation or loss of alleles, resulting in changes in the genetic makeup of a population.